Biomimetic inner helicoidal microfluidics with enhanced capillary rise for step liquid lifting mimicking transpiration

Abstract Bionic microfluidics is receiving increasing attention due to their excellent fluidic performance enabled by the biomimetic microstructures. Inspired by young pumpkin stems, we fabricate helicoidally patterned microchannels with precisely controlled morphologies using the projection micro-stereolithography (PμSL) based 3D printing technique. Our helicoidally patterned microchannels achieve approximate twice the liquid lifting height compared to the same-sized smooth microchannels because of the enhanced capillary force originated from the additional meniscus between helicoidally patterned microstructures. Moreover, the underlying mechanisms of fluidic performance in helicoidally patterned microchannels are theorized using a newly developed equation, which is also used to optimize the geometric parameters and fluidic performance of the mimicked helicoidal microchannels. Additionally, our bionic helicoidally patterned microchannels enable the high step-lifting phenomenon, simulating tall trees' transpiration. The fluidic performance of our bionic helicoidally patterned microchannels promises applications for enhanced liquid lifting, step-lifting, clean-water production, etc.